Issue #3273723 by djdevin, loopy1492, swim: fopen() error in stream_wrappers.inc on PHP 8

includes/stream_wrappers.inc

@@ -405,6 +405,12 @@ protected function getLocalPath($uri = NULL) {
   public function stream_open($uri, $mode, $options, &$opened_path) {
     $this->uri = $uri;
     $path = $this->getLocalPath();
+    if ($path === FALSE) {
+      if ($options & STREAM_REPORT_ERRORS) {
+        trigger_error('stream_open() filename cannot be empty', E_USER_WARNING);
+      }
+      return FALSE;
+    }
     $this->handle = ($options & STREAM_REPORT_ERRORS) ? fopen($path, $mode) : @fopen($path, $mode);
 
     if ((bool) $this->handle && $options & STREAM_USE_PATH) {